(defun c:acris-ray ()
  (setq screensize (getvar 'SCREENSIZE))
  (setq viewctr (getvar 'VIEWCTR))
  (setq viewheight (getvar 'VIEWSIZE))
  (setq	viewwidth (/ (* (car screensize) viewheight)
		     (cadr screensize)
		  )
  )
  (print viewctr)
  (setq	left-bottom
	 (list (- (car viewctr) (/ viewwidth 2.))
	       (- (cadr viewctr) (/ viewheight 2.))
	 )
  )
  (print left-bottom)
  (princ)
)
(defun c:1vector ()
  (setq viewdir (getvar 'VIEWDIR))
  (setq	vector-length
	 (sqrt (+ (* (car viewdir) (car viewdir))
		  (* (cadr viewdir) (cadr viewdir))
		  (* (caddr viewdir) (caddr viewdir))
	       )
	 )
  )
  (setq koeff (/ 1. vector-length))
  (setq 1v (mapcar '(lambda(x)(* koeff x)) viewdir))
  (print 1v)
  (princ)
)